Damper regulator



I N VEN TOR. W AWL/W 2 Sheets-Sheet 1 J L KIMBALL DAMPER REGULATOR Filed April 5. 1920 ITNESS:

Nov. 15,1927.

@MA/ Z/Wd Nov. 15, 1-927. 1,649,707 J. L. KIMBALL DAMPER mscwmu'on Filed April 5, 1920 2 Sheets-Sheet INVENTOR.

y W M muted Nov. 15, 1927.

HTED ST E JAMES LEWIS xmnann, or SALEM, massacnusn'rrs, ASSIGNOR T Rosanne-mon- MANN 0-, O EM, MASSACHUSETTS. 1

DAMPER REGULATOR.

which the air supply to the furnace is regu lated by the pressure in the boiler. 'Among 5 the objects of the invention are to remove.

all possible friction from the scale beam and thereby produce a more sensitive regulator, to effect a graduated movement of the plunger and to prevent fluctuation or hunting action.

Prior to the present invention, there were-and there still aretwo types of draft regulators in use. The. first and earlier 1s known as the dead-open-and-dead-shut type. The second and later is known as the floating type. -The dead-Open-anddead-shut regulator, as its name implies, operates the damper all the way from the completely open position to the completely closed position, and back again, inendless cycles. Th1s is hunting action of an extreme type. Let it be assumed, for example, that the damper is initially placed in mid position, corresponding to a normal, average steam pressure, and that the pressure starts to decrease. The damper will start to open further. For reasons presently to be explained,

it will swing wide 0 en. This greatly increases the draft, ten ing to correct the decreased pressure; but the increase'is much too rapid, with resulting OVQICOI'IBCUOII. The pressure thus builds up to a value much too high. Thereupon, the damper starts to close and will, in fact, as will presently be made clear, swing all the way back to the dead-shut position. The draft becomes thus completely shut off. The steam pressure should, theoretically, therefore start decreasing. As a matter of fact, it continues to 40 rise for a time, however, because the furnace has been forced beyond what is required to support the boiler load. When the steam pressure does, ultimately, start to decrease, it has attained a value much higher than the setting of the regulator, and with an extreme furnace condition. The pressure will, therefore, now be caused to decrease to a value much too low, whereupon the damper starts to open. As the furnace has been deprived of air for some time, it .can not instantly respond to the draft thus admitted, so that the damper continues in its opening movement and is soon carried over again to the extreme open position, producing an excess of air gain. The damper 1s th s always part way. only, and not all the way.

maintained in an extreme position, resulting either'inan excess or a deficiency of airv supply, as. the case maybe. Occasionally, under extraordinary conditions, the damper is checked in an intermediate position, and its movement reversed before a complete stroke has been made, but this is most unusual. Theusual operationis by complete strokes, back and forth between the deadopen and the dead-shut positions. f

To each particular value of the steam pressure there corresponds a certain. particular position that the damper should occupy. Withthe damper in this position, the draft to the furnace will besuch as to tend to maintain the steam at the corresponding pressure value. When there is a change in steam pressure'due, for example, to a change in load, the damper should be moved to the position corresponding to the'new value of the steam ressure. The trouble with regulat'ors of t e dead-open-and-dead-shut type is that the damper does not stop in theposition corresponding to the new pressure value, but travels beyond to either the deadopen or the deadshut position, as the case may be.

' Floating-type regulators move the damper Theoretically, a small change in pressure conditions will cause a small movement of the damper to a position corresponding to the changed pressure value. A large change in pressure conditions will similarly cause a large movement of the damper. As these changes are continually going on, the damper is continually moving or floating. The

floating type regulator in common use comprises a regulating motor and an element for controlling the position and the direction of operation of the motor. The motor may be hydraulic, electric, and the like, and the element may be a pilot valve, a pilot switch, or some other mechanism. The element usually has a neutral position, in which the motor is maintained against operation, and two effective positions, in which. it controlsthe operation of the motor in opposite directions. A change in the normal conditions causes the element to be moved out of its neutral position, into one.of the effective positions, and this, in turn, causes the motor tooperate in the proper direction tocause a return to the normal conditions. When the regulating motor commences to I sure starts to decrease.

operate, itactuates a compensating device for returning the element to the neutral pois required by the changes in pressure. In

the case of hydraulic motors, for example, this is caused largely by the pilot valve sticlging or binding. by friction. This frictional binding it is impossible,'in practice, to avoid. The compensating dep'ce must, therefore, overcome this frictional. inding action before it can begin to operate to return the valve stem to its neutral position, with the result that the motor plungeiyhas meantime travelled too far, and caused over-correction.

'ith the damper in mid-position, for example. let it be assumed that the steam pres- The damper is thereupon floated toward the extreme open position. increasing the draft to the furnace. Theoretically, the damper should stop at a )osition such that the resulting draftwill jllSt balance the decreased value of the pressure. But the damper does not stop there; it travels on beyond t lat point,not to the extreme open position, but a considerable distance beyond where it should have stopped,

.- In technical language. it hunts. The damper having travelled too far in this direction, the

- pressure builds up to a value much too high.

off is Thereupon the damper is floated in the reverse direction, but again too far. and again with consequent over-correction, this time in the opposite direction. The action of the regulator, therefore. is such that the damper continually overtravels, that is hunts, in opposite directions. There is thus a continual,

and unnecessary reversal of the boiler operations.

According to the present invention. the compensating device is not permittedto act continuously,-as is the casewith floating regulatois,but intermittently only. The motor plunger is provided with a graduated, or stcp-by-step, movement, and'a similar ac tion is thus transmitted to the compensatingdevice. Each step of the operation of the motor is normally well defined, and no cutssible under normal operating conditions tween the cut-olt points at the beginning and the end of each step. The regulator of the present invention resembles the floating-type regulator in that the damper is moved part way only, and not to its extreme positions, but it is ditlerentiated from the floating-type regulator in that the damper does not float, but is moved by steps in response to large variations in pressure, and is normally stopped at the end of each normal step to await a further comparatively large variation in pressure before it is moved again. As the operation of the motor plunger is definitely terminated, and the plunger quent fiuctuationor hunting action, is eliminated.

To accomplish these objects, I have produced, according to the specific embodiment of the invention that is herein illustrated and described, a regulator in which the pilot valveis operated by electric magnets, using a pressure circuit-closer for making an electime contact to operate the magnets. Heretofore, it was customary to connectthe pilot valve direct to the scale beam, but the friction necessary to operate the pilot valve was such as to interfere with the close regulation of the steam pressure.

In the accompanying drawings, illustrating one embodiment of the invention, Fig. (1) is a vertical view. a part of whichis in section and Fig. (2) is a vertical section of the pilot valve with its operating mechanism. removed from the regulator. Like numerals refer to similar parts in the various views.

A diaphragm (1), diaphragm chamber (2). pressure cap (3), scale beam (4), and weights (5) constitute an operating device for a pressure circuit closer. The n is responsive to pressure. such as the ressure of steam from a boiler, and the c 1amber (2) is therefore shown connected to-a source of boiler pressure at (6). Motion is imparted by the scale beam to the circuit closer mounted on the slate board by means of spindle (7). The circuit closer consists of two insulated contact points (8) and (9) which make art electric contact on-opposite sides of a revolvable contact disc (27). The contact points (9) and (8) are respectivel connected with electromagnets (10) and n of which 12 and (13 are the the these plungers are in turn connected to a pilot valve lever (18) at (19)'and (20),-respectively. The left-hand end of lever (18) is connected with pilot-valve stem (21), \vhichlits pilot-valve body (22).

the pilot valve (:22) is prefer ly of t no isten type. (34) is t to inlet for water or 0t ler fluid under prwsu're, (35) is the waste or overflow, (33) is a. pasage leading to the H5 Referring more particularl to F i (2) the two cylindrical portions 38 and 39 a of the valve stem (21). When the stem is raised, water is admitted at port (42) and communicates through passage (32) to thebottompf the motor; at the same time, exhaust port- (43) is opened to atmosphere,

allowing water to escape from. the top of the motor. Whenthe stem (21) is lowered, admission port (42). and exhaust port (43) are closed, and admission port (44) and exhaust port (45) are opened, reversing the motion of the motor. -It will be understood that any pressure escaping from the top end of the motor will be exhausted to the bottom end of" the valve, where a cored passage on the side of the valve, not shown, allows this water to reach the top of the valve and go to waste at overflow connection (35).

It will be noted that the pilot Valve stem (21) normally assumes a neutral position, in

which no pressure can be admitted or exhausted to or from motor cylinder (24). The pilot valve stem may also be actuated upward y one of the magnets to admit water under pressure to the bottom of the cylinder, thus to effect the upward movement of the plunger (23) and downward by the other magnet,

. to admit water under pressure to the top of the cylinder, thus to efiect the downward movement of the plunger.. Each dash pot and armature are of suflicient weight to hold the pilot-valve lever fulcrumed, while the opposite magnet is operated to move the valve in a certain direction.

The contact sheave (27) is mounted on a vertical stud (31) and isthreaded to this stud with a coarse-pitch thread. It is rotatable to travel either in an upward or downward direction by the movgnen't of the motor plunger (23). After the cont-act has been made by the movement of the scale beam, (4), the pilot valve (22) is operated to move the plunger (23) which, in turn, revolves the contact sheave (27) in the direction to break the circuit and cause the motor plunger to come to rest. 1 The armatures being connected to oil dash pots, the time required for the plungers of these dash ots to settle into their bottom osition an bring the pilot valve back to 1ts neutral position is such as to allow the A motor plunger (23) to have traveled momenthe contact points (8) and(9). T

tarily after the current has been broken. In

this way, the motor plunger (23) is compelled to operate throughout a definite distance or step and the contactor disc (27) 'is moved to a central position half wagibetween a uniform variation in pressure in either direction before the contact is again made and also prevents arcin the current.

A definite cut-o is thusefi'ected as soon as the circuit broken, but the motor con tinues to operate between cut-ofi points throughout ill distance or step, the valueof s allows.

which is determined by the time lag of the dash pot. This time lag, which regulates the return of the valve stem to its neutral position, may, of course, be adjusted to adjust the length of the steps oftravel of the motor plunger.

The main electric source of supply is conneted at (25). Thisiconnectio extends to one side of coil (14). The opposite side of the coil is connected to contact point (9) through a flexible connection-(36). A connection also extends from (25) to coil (15).

The op osite side of this coil (15) is connected t irough flexible connection (30,) with contact point (8). The opposite side of the line (26) is connected with the screw spiudle (31) on whichthe contact disc (2'?)- is mounted.

The principle of the operation is as follows: The pressure of the steam in the boiler (not shown) is communicated, by way of the diaphragm chamber (2), to the flexible diaphragm (1). Variations in the steam pressure thus cause corresponding movement of the diaphragm, and this movement is transmitted to the scale beam (4). As the steam pressure varies, therefore, the scale beam will be c auscd to pivot up and down sition. When the motor plunger is lowered,

it will cause corresponding actuation of the damper towards the full-open position through an impelling cord (48). -The motor is thus automatically operated in either'of its two opposite directions to operate the damper in opposite directions and thus to regulatethe draft. The temperature of the furnace is therefore automatically controlled to va the steam ressure in the boiler according to the dra With this brief explanation of the principle of operation. the specific description that is about to follow will be readily understood. .Let it be assumed'thatthe weights (5) will just balance a normal steam pres sure in the diaphragm chamber. When the steam pressureexceeds the predetermined valuefor which the scale beam (4) is thus weighted, therefore. the'sc'ale beam will be caused to ivot upward about the pivot (28). The scale am moves entirely independently of the motor, which remains stationaryuntll the pressure becomes sufiiciently great so as to cause the contact point 9 to engage the underside of the contact disc (27). circuit is then established through the coil (14), energizing the magnet 10) to attract the armature (12). p The d and the valve spindle (21 will therefore hecome raised, and fluid on or pressure will be admitted," through the port (32), tothe portion of the c linder (24) under the plunger (23). The unger (23)-will then move upward, and t e weight (46) will actuate the damper (47) towards the' closed position, thereby shutting off, by so much, the draft to the furnace. v i

To the top of the plunger (23 is secured the upper end of a cord (29) t at extends ardund the contact disc (27), a weight (33 being secured tothe other end of the oo' (29) to take up the slack therein and to pro-' vide suilicient tension in the cord to cause it to engage the contact disc firmly. As soon as the motor plunger starts its upward travel, therefore, to permit the weight (46) to actuate the damper, it effects, also, a slight rotative movement of the contact disc (27) by 'means of the cord (29). This slight movement. of the contact disc (27) is in such direction as to break contact with the contact point (9), and thus to open the circuit of the coil (14). The'magnet (10) becomes deenergized as soon as 'contactis broken between the contact point (9) and the disc cause the dash (27), allowing the dash-pot plunger (16) to'settle into its bottom position and the spindle (21) of the pilot valve to return to its neutral position. This. in turn. results inthe p1 r (23) being brought immediately to in the positionthat it then oc- CRIMES. But the motor can not stop moving soon as contact is broken between theta)!- tact disc (27) and the-contact int"(9),he t. prevents t e immediate return of the v ve stem to the neutral Vsition. Thevalve is purposely keptppen n a timeinterval by the dash pot. this i time interval; the motor completes a definite step of operation, determined as to length by the adjustment of the dash pot.

' If the steam pressureshould continue to increase, the operation will be repeated, the plunger moving up to a second 8.111] on, malnngfrom ten to twelve stops before the strokeis completed and causing corresponding actuation of the damper 47. Whenever the steam pressure decreases, the weights (5) cpuse the scale beam (4) topivot downward about the pivot (28) independe'ntly of the motor, and contact Soint 8) engages the top of the contact isc (2 establishing a circuit through coil (15), energizing magnet (11.) and attracting armature (13) the dash-pot plunger (17) will thereupon become raised, and as lever (18) is fulcrumed on daah pot rod (16) at (19), spindle (21) will be lowered, opening port -p'ot. plunger (16) means:

enter the to the plunger (23) downward. As the plunger moves, it actuahs the dam r in the op osite direction to increase e draft to the unmee. At the same time, it turns the contact disc (27 which breaks the circuit and allowing armadeenergizest emagnet (11), tom (13 to be released and dash-pot plunger 17) to settle into its bottom pose (33) and allowin fluid under remureto' ot t e cylinder (M and'forceas on the upward stroke. 1 When'the steam pressure rises too high,"therefore, the damper (47) becomes closed by steps, In to large variations in ressure, to shutefi the furnace draft, and t s permits the pressure to fall; and when the pressure falls too low, the damper is opened by corresponding stefi increasing the draft, thus again raising steam pressure. In K practice, the lunger would seldom make a complete stro' from one end to the opposite end of the motor cylnder (24), but would .hold to a position in its travel" which would sup ly the -.M m air to the furnace to burn t e' fuel and maintain a uniform steam pressure. As chan in load or furnace conditions would take place, the plunger would move vto'another:

stage. in its travel, which would correct the change and bring the steam p w: hclrto normaL- The temperature of the is thus automatically controlled to keep" the steam pressure at a *valu'e approximately-corres ndingto the load." i

order to obtain a better understanding of the o tion, let it be, for example, at the mean averagewalue' of the steampressure is 100 fpounda, and that a change n load has caused-timpressure to become. mcreascd to 101 Let it be assumed, further, that theregulator is ad justed to operate the damper when the pres: sure increases or decreases b increments of one pound. "No value of t e p between 100 and-101 poimds canth result in any change in the m'tionoi the J 1 1: per, and the regulator "in not respond to such slight changes. -The scalebeam will merely more up and down, but without establishing contact between the contact disc (27 and either "of the contact points (18) an (9). As soon as the lot-pound va ue has been reached, however, the damper will suddenly be actuated one step, from the position correspondin to- 100 pounds to the position correspon mg to 101 unds, and it will there 'he'sto pedand'hel statio It will not travel end that point, an then retnrn like floating regulators; that is, it will not hunt. It stops at the lill-p'oundtpoint and stays there, until the p o either builds up to 102 pounds or falls to 100 pounds; for the contact disc 27) is always returned to a position substantiall half-way between the contact points (8) "an (9).

No change in the pressure between these values 100 and 102 can budge the damper from its 101-pound position. Should the pressure build up to 102 pounds, the damper will suddenly or abruptly be moved a second step to the position corresponding to-102 pounds, and there stopped. Similarly, if the. pressure should fall, instead, to 100 pounds, the damper will suddenly be returned a step from the 101-pound position to the 100- pound position, and there stopped. In technical language, the damper lags behind the pressure value until the'pressure change reaches a point corresponding to the next stepped position. The damper is then moved a whole step up to this position and stopped. In floating regulators, on the other hand, the damper floats first behind and then ahead,--it overregulates, or hunts. In the regulator of the present invention, the damper can not possibly overtravel or hunt, in the one direction or the other,'with the result that the boiler load or pressure is maintained approximately balanced at each stepped position until it has increased or decreased sufiiciently 'to cause actuation of the damper to a new stepped position.

Experience has shown that small variations in pressure do not ordinarily indicate either a permanently rising or a permanently falling load. If let alone, such small variations become rapidly dissipated and the pressure thus returns to normal without regulation. Floating and deadopen-and-dead-shut regulators respond readjly to such small variations in pressure,'thus causing a disturbance in, rather than a correction'of, the conditions. i

.The step-by-step regulator of the present invention, on the other hand, makes no at.- tempt to regulate for such small fluctuations of pressure. The damper is maintained stationary, notwithstandin such small fluctuations, and is not move until. the pre$ure variation has become built up or down to a sufficiently large value to indicate a permanently rising or a permanently falling load. Then, and then only, will the circuit of the electro-ma etic devices for actuating the pilot valve ome closed. Then, and then only, will the dam er be actuated by the hydrauli motor, an it will not be permitted to float back and forth but it will be moved through a certain distance or step, and there normally stopped. It will be stopped because, as soon as the motor started, it immediately opens the circuit of the electro-magnets, but the motor and, therefore, the damper, continues operating throughout a' definite distance or step by virtue of the dashpots 16,17. These dashtivel'y rapidly.

in pressure in one direction or the other must take place before the damper will again be actuated, and it will then again be moved throughout a step, and then again stopped.

The damper is brought to a sto at the end of certain distances or steps 0 movement, and is maintained against movement, or nonresponsive, at theend of each step until the pressure has changed sufiiciently to cause a new ste of movement. The damper is thus operate by steps in response to comparatively large variations in pressure and is stopped at the end of each step, where it remains in position until there is a further predetermined variation in pressure, when the operation is repeated. These steps may previously be designed so asto harmonize most closely with the demands of the particular plant under consideration.

Ordinarily, and normally, the steps of travel will be of substantially equal length.

:fact,.in some types of step-by-step regulators now on the market, each step of travel is fixed in length and position. According to the present invention, however, it is some times possible, under abnormal conditions, for the length of the steps to become automatically slightly increased in accordance with the requirements of such abnormal con dltions.

A few words will make clear the distinction between normal "and abnormal operating conditions. It has been tacitly assumed, in the foregoing description, that the pressure changes take "place comparatively slowly and gradually,ias is actuallythe case under normal operating conditions. When the pressure was described asrisin'g from I00 .to 101' pounds, causing contact to be made between the contact member (9) and the contact disc (27), the pressure rise was considered tobe sufliciently slowly so that contact would be broken again immediately as soon as the contact disc (27) was started moving upward.

Under abnormal operating conditions,-

however, the pressure might rise so rapidly or abruptly as to cause. e contact member 9) to move upward as fast as, or even faster than, the upward movement of the-contact disk (27). In that event, contact between the contact disk (27) and the contact member (9) will'be maintained, notwithstanding the upward movement of the contact disk (27). The length of the step will then depend upon how soon contact is broken be tween the contactmember (9) and the com tact disk (27). And the same is true when the pressure becomes j decreased com In fact, it the boiler s dhl d burst, the contact member (8) would mainta-in contact with the contact disk (27) unei the motor'hus. completed more,

Emu the dam r 'ht bo moved-mu is strokefrom to full shut Even when the stepssre ofunequell I a.

' however, there." willnct' be hunting: or

balanced by greater .ccmplicotions in struc= tors. and increased sensitivity in operation.

' neither of which is always desirable.

The term step-bysste operation, or its 4 equivalent, is employed herein in the speci= fication and claims to define an operation as described above, in which the definite completion of each particular step, us down mined by boiler or other load conditions, is

normally ed, but without hunting,--= that is, without overtrsvcl of the rcgulstor, or trove! to points beyond what is required 5 by such boiler or other load conditions. i The use oi"v such term, as so ded, excludes mom within its scope the old floating-type rcguls tors, butwithout involving circumlocution oflungu I e. 7

,Althcug I have described my inventionin connection with regulation of; dam ere, I do not Wish to limit-its use, but to min it broadly, as regulators of this class are used for a variety of purposes, such as the operationvof valves for controlling the speed of fan engincs'and turbo blowers,.the operstion of rheoststs to controlthc s I d of elsc tric motors driving forces or in need prm= sure fans, the controlling oflevcr valves to reducev end rcgulstc steam or other fluids under pressure and for other purposes. Nor

is the invention necessarily restricted strictly to pressure systems, as it is equally applicable, for example, to temperature-control regulators; v 1

H'cvin fully described my invention, whet aim as new and desire to secure by 4' Letters Patent of the United States, is

1. The combination with a valve and s motor adopted to be. operated thereby, of electromagnetic menus for controlling" the valve, means for energizing the electromag netic menus to eficct the operation of the valve, and means controlled by the motorfor decncrgizing the electromagnetic means, thereby rendering the valve incfi'cctivc, upon the motor commencing to operate.

2. The combinstion with a motor and s valve for operating the some having a, neu: tral position in which it is ineffective and two cflective ositions in each of which it controls the motion of operation of the motor, electromagnetic means for actuating. the valve to one or the other of its efiective I ncense? valve for operating the motor, electric mogtion upon the motor commencing to operate,

3., The combination of s valve arranged to normally assume a, neutral position and to control the flow of fluid through said valve by being moved-out of its neutral position, a rocker-arm, a plurality ofclectromagnets, means pivotelly connecting the electromagnets with the arm, the pivotal connections serving us fulcrum points for the rocker arm, and arrangements whereby the rocker arm is held stationery at esch of said pivotul connections while the opposite magnet: is opcrnted to movcthe valve in s certoi direction from its neutral position. I

4. In s.- damper regulator, the combination of a motor for operating the damper, a pilot nets for operating the pilot valve, one magnet controlling the upward movement of the motor and the other magnet controlling the downward movement of the motor, spreS- sure operated circuit closer for independent ly operating the magnets, and a movable contsctor controlled b the movement of the motor for breaking 't e circuit and causing the pilot valve to assume a. neutral position and bring the motor to rest.

5. In o damper regulator the combination of a motor for operating the damper, a. pilot valve for operating the motor, electric-mag nets for operating the pilot valve, one msgnet controlling the upward movement of the motor and the other magnet controlling the downward movement of the motor, u pressure operated circuit closer for independently operating the magnets, and a contact disc thrcsdobly mounted on a. screw spindle and rcvolvsblc by the movement of the 1110- tor for brcskin'g the circuit andcausing the pilot valve to assume a neutral'position and bring the motor to rest.

6. In a pressure system, the combination with means comprising a valve having a stem adapted to occupy a neutral position in which the valve is inefibctive and two eficctive positions inwhich the valve is adapted to control an increase and a. decrease respcctively in the pressure in the system, two electromugnets for respectively actuating the valve stem to its effective positions, u contact disk electricullyconnected to the elec-' tromognets, at pressure chamber connected to the pressure system having a diaphragm, a scale beam connected to the diaphragm, whereby the movements of the beam are rendered responsive to the values of said pressure, u spindle connected to the scale beam,

contact members respectively electricolly connected to the electromagncts secured to positions upon the respective contact members contacting with the contact disk intresponse to the scale beam being moved in one or the other direction, and means controlled by the valve for separating the contact disk from its contacting contact member upon the commencement of the operation of the valve to cause the return of the valve stem to its neutral position. I i

'7. In a pressure system, the combination with means comprising a valve for controlling the pressure in the system, of electromagnetic means having Efipilurality of arma-. tures positively connected to the valve for actuating the valve in difierent directions,

and means controlled in accordance with the pressure in the system for energizing the electromagnetic means to selectively actuate the a-rmatures.

8. In a pressure system, the combination with means comprising a valve for controlling the pressure in the system, of an electromagnet having an armature positively connected to the valve for actuating the valve, a scale beam responsive to the pressure in the system, means connected to the scale beam for controlling the electromagnet, and

' means controlled by. the valve for rendering the -scale-beam-connected means inefwith a fluid motor for controlling the presfective.

9. In a pressure system, the combination with means comprising a valve having a. stem adapted to occupy a neutral position in which the valve isinefi'ective and two effective positions in which the valve is-adapb ed to control an increase and a. decrease re spectively in the pressure inthe system, of electromagnetic means for selectively actu ating the stem to its eflect-ive positions, means ing the electromagnetic means inefiective to further operate the controlling means upon a predetermined limited operation of the controlling means. i j

11. In a pressure system, the combination with a motor for controlling the pressure in the system and a valve for controlling the motor, of electromagnetic means for controlling the valve, the valve being efiectlve to control the motor only ivhile operated upon by the electromagnetic -means, means responsive to the pressure in the'system for to further control the valve upon v a predcter mined limited operation of the motor.

12. In a pressure system, the combination with a motor operable to control the pressure in the system, of electromagnetic means for efi'ecting the operation of the motor, means responsive to the pressure in the system for rendering the electromagnetic means eli'ective,and means for rendering the electromagnetic means ineffective to further operate the motor, thereby bringing the motor to rest, upona predetermined limited operation of the motor.

13. In a pressure system, the combination with a motor for controlling the pressure in the system, and a valve having a neutralposition in which it is inefi'ective and un effective position iii which the operation of the motor is effected, of electromagnetic means responsive to the pressure in the s stem for actuating the valve to the effective posit-ion, and'mea-ns forreturning the valve to the neutral position and effecting a stopping of the motor upon a predetermined limited operation of themotor.

14. In a pressure system, the combination sure in the system, and a normally closed valve adapted, when open,'to admit fluid under pressure to the motor, of, electromag netic means operable in accordance with the pressure in the system to control the valve, and means for rendering the electromagnetic means ineffective, and thereby permitting the closing of the valve and effect- :ing a stopping of themotor, upon a predetermined limited operation of the motor.

15. In a pressure system, the combination with a motor operable to control the pressure in the system, .and a valve having a neutral position in which it is ineffective and two effective positions in which it controls the operation of the motor in opposite direction's, electromagnetic means for selec- .tively actuatingthe valve to its effective positions, means responsive to the pressure in the system for controlling the electromagnetic means, and means controlled by the motor for rendering the electromagnetic means ineffective, thereby causing the valve to assume the neutral 16. In a pressure system, the combination with a motor for controlling the pressure in the system, a valve for controlling the motor, and a scale beam responsive to the pressure in the system, of electromagnetic means for controlling the-valve, means controlled by the scale beam for rendering the electromagnetic means effective to control the valve, and means controlled by the motor for renposition and efl'ecting astopping of-the motor.

&

- a v I dering the electromagnetic means ineffective to further control the valve upon a predetermined limited operation of the motor.

17. In a. pressure system, the combination with a motor for controlling the pressure in the system having a range of operation be tween predetermined limits, and a valve for controlling the motor, of electromagnetic means for controlling the valve, the valve being effective to control the operation of the motor only when the electromagnetic means is effective to control the valve, means operable upon a variation in pressure in' the system to render the electromagnetic means ffective, and means operable to render the electromagnetic means ineffective, thereby rendering the valve ineffective and stopping the motor, upon a predetermined limited operation of the motor. L

18. The combination with a movable member adapted normally to occupy a neutral position, of electromagnetic means for selectively moving the member to one side or the other of thc neutral position, means for energizing the electromagnetic means to effeet the selective movement of themember,

' and means for deenergizing the electromagnetic means, the member being adapted thereupon to return to the neutral 19. In a pressure system, the com ination with means comprising a valve having a stem adapted to occupy a neutral position v in whichthe' valve is inefiective and two Bi fective' positions in which the valve is adapted tocontrol an increase and a decrease respectively in the pressure in the system, means controlled by the pressure in the sys tem for selectively actuating the stem toits effective positions, and means controlled by the valve for rendering the pressure-controlled means ineffective upon the valve-con trolled means commencing to operate.

20. In a pressure system, a motor forcontrolling the pressure in the system, a valve for controlling the motor, a scale beam for controlling the valve, a diaphragm coutrollcd in accordalwe with the pressure in the system connected to the scale beam, and means connected to the motor whereby the valve is operated to control the operation of the motor step by step.

21. In a regulator comprising a motorand a pressure-responsive device, a controlling element for said motor, and means operated by the motor and the pressure-responsive device for ell'ecting an intermittent control of said controlling element, for effecting the operation of the motor step by step.

22. In a regulator comprising a motor and a pressure-responsive device, a controlling element for said motor, and auxiliary motive means operated by the pressure-responsive device and the motor for effecting an intermittent control of the controlling osition.

meager element, whereby the motor is operated in contmlling the" controlling element, whereby 1 the motor is operated in predetermined stages of travel with a well defined period of 1 rest between said stages. v

2a. In a regulator comprising a motor and a prcssure-responsivo device, a controlling element for said motor, means operated by the motor and the-pressure-responsive-device including a time-lag element for intermittently controlling the controllin element 'to efiect a step-by step control of t e motor.

25. In a regulator comprising a motor and a pressure-responsive device, a controllingelement for said motor, and auxiliary motive means operated by the pressure-responsive device and the motor including a timelag element for intermittently controlling the controllingelement to effect a step-bystep control of the'motor.

26, In a regulator comprising a motor and a pressure-responsive device, means to control the operation of said motor in opposite direct-ions, said means includingtwo electromagnets, one of said vmagnets controlling the o eration of the motor in one direction and tie, other magnet controlling the opera; tion of the motor in the opposite direction, a pilot switch in circuit with said magnets and controlled by the pressure-responsive device, said pilot switch being arranged to make an electric contact on variations in pressure actlng on the pressure-responsive device to operate either one or the other magnet, and means operated by the motor for breaking said contact after the motor has operated for a predetermined period. 0

27. In a regulator comprising a motor and a pressure-rcsponsivc device, a controlling element for said motor, auxiliary motive means for operating the controlling element, and means jointly controlled by the motor and the prcssure-responsive device for controlling said auxiliary motive mcans.

28. lira pressure regulator, in combinahon, a pressurc-rcsponsive device, a motor for controlling the pressure to which the pressure-responsive device is adapted to be subjected, a valve for controlling the motor, means operated in accordance with variations in the said pressure to effect an abrupt operation of the valve to open position to effect operation of the motor, and means operated b the motor for closing the valve to render t 1e motor inefiective.

29. A regulator having, in combination, a

pressure-responsive device, a motor for conoperatin to effect the operation of the mo tor step by step. a

31. A regulator having, in. combination, a pressure-responsive device, a motor for controlling the pressure to which the pressurerespons'ive' device is adapted to be subjected, two elements having two relatively effective positions in which they are adapted to control the operation of the motor in opposite directions and a relative neutral position in which they are inefiective, and means controlled by the pressure-responsive device and the motor for relatively actuating the elements to the relative eiiective and to the relative neutral positions to eflect the operation of the motor step by step.

32. A regulator having, in combination, a

pressure-responsive device, a motor for .con-' trolling the pressureto which the pressureresponsive device is adapted to be subjected, an element having two effective positions in which it is adapted to control the operation of the motor in opposite directions and a neutral position in whichtit is ineflective,

means controlled by the pressure-responsive device for actuating the element to the efi'ective positions, means controlled by the motor for actuating'the element to the neutral position, and means for rendering the operation of the element to one of the said positions abrupt.

33. A regulator having, in combination, a pressure-responsive device, means for controlling the' pressure to which the pressureresponsive device is adapted .to be subjected, electromagnetic means having a plurality of arma-tures positively connected to the pressure-controlling means for actuating the pressure-controlling means in different directions, and means controlled by the pressure-responsive device for energizing the electromagnetic means to selectively actuate the armatures.

34. A regulator having, in combination, a pressure-responsive device, a motor for controlling the pressure to which the pressureresponsive device is adapted to be subjected, an element for controlling the motor, means controlled by the pressure-responsive device for operating the element in one direction to efi'ect the operation of the motor, means controlled by the motor for operating the element in another direction to eifect a stopping of the motor, and means for ensuring a predetermined degree of operationof the motor before the motor is stopped;

35. A regulator having, in combination, a

pressure-responsive device,a motor for controlling the pressure to which the pressure responsive device is adapted to be subjected, an element "ton-controlling the motor, means controlled by the pressure-responsive device for operating theelement intermittently in one direction to effect astep-by-step opera.- tion of the motor, means controlled by the motor for operating the element intermittently in another direction to successively terminate the steps of operation of the motor, and means for ensuring that the motor shall operate to a predetermineddegree at each step of its operation before the motor is stoppedat the end of each step of its operation.

36. A regulator having, in combination, a

pressure-responsivedevice, a motor for controlling the pressure to which the pressureresponsive device is adapted to be subjected, a valve for controlling the motor, means. controlled by the pressure-responsive device for operatingthe valve in'one direction, means controlled by the motor for operating the valve in another direction, and means for rendering the operation of the valve in one of the said two directions abrupt. i

37. A regulator having, in combination, a pressure-responsive device, a motor for controlling the pressure to which the pressureresponsive device is adapted to be subjected, a valve for controlling the motor, means controlled by the pressure-responsive device for opening the valve, means, controlled by the motor for closing the valve, and means for rendering one of the said two operations of the valve abrupt.

38. A regulator having, in combination, a

pressure-responsive device, a motor for controlling the pressure to which the pressureresponsive device is adapted to be subjected, an element for controlling the motor, means controlled by the pressure-responsive device for operating the element in one direction, means controlled by the motor for operating the element in another direction, and meansfor rendering the operation of the element in one of the said two directions abrupt.

39. A regulator having, in combination, a pressure-responsive device, a motor for controlling the pressure to which the pressureresponsivedevice is adapted to be subjected, an element having two effective positions in which it is adapted to control the operation of the motor in opposite directions and a neutral position in which it is ineffective, means controlled by the pressure-responsive device for actuating the element to'the effective positions to efiect the operation of the intermittentl motor in opposite directions, means controlled by the motor for'actuating the element to the neutral position to efiect a stop: ping of the motor, and means for ensuring a predetermined degree of operation. of the motor beforethe motor is stopped.

to. A. regulator having, in combination, a

' pressure-responsive device, a motor for conmeans controlled by the motor ior'actuating the element intermittently to the neutral position to successively terminate the steps of operation of the motor, and means for ensuring that the motor shall operate to a predetermined degree at each step of its op eration before the motor isstopped at. each step of its operation.

lfn apparatus for automatic draft con- "ctro'l, a draft regulator, impelling means therefor, a motor for driving the same in either of two directions, controlling means for causing step by step'mov'ement of said motor in either direction, a pressure motive mechanism capable oi? acting in any position of the impelling means to operate said con= trolling means, and a source of pressure dependent upon the draft regulated for actu= ating said pressure motive mechanism.

d2,- A draft regulator having, in combi-v nation, means 0 erable in either of two di-- rections for regu ating the'drait, a motor for actuatin, the draft-regulating means in either 0 the said two directions, a pressure device the pressure u on which is controlled by the draft, control .ing means for causing step-by-ste operation of the regulating means by t e motor in either of the said two directions, and means controlled by the pressure device and operable independentl of the motor for operating the controlling: means, 6

st. in a fluid system in which the condi:

tion of the fluid in the system controlled by a draft, a motor operable in either of two directions for regulatiug the draft, a

pressure device the pressure upon which is controlled in accordance with the condition of the fluid in the system, controlling means for causing step-by-step operation of the motor in either of the saidtwo directions, and means controlled by the ressure device 7 and operable independently or the motor for operating the controlling means.

M. in a draft-control regulator for boilers, I

means operable in either of two directions for regulating the draft, a motor for driving l esa-rev step.

the draft-regulating means in either of the said two directions, the motor being adapted to occupy a plurality of positions each corresponding to a predetermined-value of the boiler load, an element for controlling the starting of the motor in elther direction,

load at which the motor started, whereby the motor is operable step by step to operate the draft-regulating means step by ste 45, In a fluid system, a motor for contro lin the condition of the fluid in the system, the motor being adapted to occupy a plurality of positions each corresponding to a predetermined value of the condition of the fluid in the system, an element for controlling the startingof the motor, a pressure device the pressure upon which is controlled in accordance with variations in the condition of the fluid in the system, means controlled by the pressure device for actuating the element to efiect the starting of the motor, means for reventing the motor from starting until t e said variations attain a predetermined value, and means for normally stopping the motor when the motor has been actuated to a position corresponding to the value of the condition of the fluid in the system at which-the motor wasstart' ed, whereby themotor is operable step by (46. In a fluid system, a motor for controlling the condition of the fluid in the system, the motor being adapted to, occupy a plurality of positions each corresponding to a predetermined value of the condition of the fluid in the system, two elements having a relative neutral position in which they are inefiective and a relative edective position in which they edect the'starting of the motor, means controlled in accordance with varie tious in the condition of the fluid in the systerm for relatively actuating the elements to,

the relative edeotive position when the'said variations attain a redetermined value to efiect the startin o themotor, and means for normally re atively returning the elements to the relative neutral position to stop the motor when the motor has been actuated to a position corresponding to the value of the condition of the fluid in the system at which the motor was started, whereby the motor is operable step by step.

47. In combination, a pressure device, a motor for controlling the pressure upon the pressure device the motor being adapted to occupy a plurality of positions each correout Variati0ns attain a predetermined value to sponding'to, a predetermined value of the variations attain a V 7 means for norma y stopping the motor when the motor has been actuated to a position corresponding to the value of the pres sure upon the-pressure device at which the motor was started, whereby the motor is operable step by step.

48. In combination, a pressure device, a motor for controlling the pressure upon the pressure device, the motor being adapted to occupy a plurality of positions each corresponding to a predetermined value of the pressure upon the pressure device, two elements having a relative neutral position in which they are ineflective and two relative efi'ective positions in which they control the starting of the motor in opposite directions, means controlled in accordance with variations in the ressure upon the pressure device for relatively actuating the elements to the relative effective positions when the said effect the starting of the motor in one or the opposite direction, and means for normally relatively returning the elements to the relative, neutral position to stop the motor when the motor has been actuated to a position corresponding to the value of the pressure upon the pressure device at which the motor was started, whereby the motor is operable step by step.

49. In a fluid system, a motor for controlling the ondition of the fluid in the system, a valve for controlling the motor, and means controlled in accordance with the condition of the fluid in the system fon opening and closing the valve toeflect a step-by-step operation of the motor. 7

50. In a fluid system, a motor for controlling the condition of the fluid in the system, two elements having a relative neutral position in whichthey are ineflective and a relative eflective position in which they control the operation of the motor, means controlled in accordance with the condition of the fluid. in the system for relatively actuating the elements to the relative eflective position,

andmeans for relatively returning the 'ele-' ments to the relative neutral position at stepped points in the operation of the motor to eflect step-by-step operation of the motor. v

51. In combination, a pressure device, a motor operable step by step to control the pressure upon the ressure device, two elements for controlllng the motor having a relative neutral'position in which they are ineffective and two relative effective positions in which they control the operation of the motor in opposite directions, means controlled by the pressure device for actuating the elements to the relative efiective positions, and means for returning the elements to the relative neutral position at stepped points in the operation of the motor to effeet a step-by-step operation of the motor.

52. In a pressure system, 'a motor operable in either of two directions for regulating the pressure in the system, controlling means for causing step-by-step operation of the motor in either of the said two directions, andmeans controlled in accordance with the pressure in the system and operable independently of the motor for operating the controlling means.

53. In a pressure system, means operable in either of two directions for regulating the pressure in the system, a motor for actuating the regulating means in either of the said two directions, controlling means for causing stepby-step operationof the regulating means by the motor in either of the said two directions, and means controlled in accordance with the pressure in the system and operable independently of the motor for operating the controlling means.

54. In a fluid system,'means operable in either of two directions for regulating the condition ofthe fluid in the system, a motor for actuating the regulating means in either of the said two directions, a pressure device the pressure upon which is controlled in accordance with the condition of the fluid in the system, controlling means for causing step-by-step operation of the regulating means by the motor, in either of the said two directions, and means controlled by the pressure device and operable independently of the motor for operating the controlling means. a

55. In a fluid system, means for controlling the condition of the fluid in the system, means controlled in accordance with the condition of the fluid in the system for starting 56. In .a fluid system, means for control-' ling the condition of the fluid in the system electric means for starting the operation o the controlling means, a switch for controlling the electric means, means controlled in accordance with the condition of the fluid in the system for closing the switch to cause the electric means to effect the starting of- .the operation of the controlling means,

means controlled by the controlling-means for opening the switch to efi'ect the stopping of the operation of the controlllng means,

and time-lag means for delaying the stop .ping of the operation of the controlling means.

57. In apparatus for automatic draftcone trol, a motor operable in either of two directions for regulating the draft, controlling means for causing step-by-step operation of said motor in either of the said two directions, a pressure mechanism the pressure upon which is controlled by the draft, and

means controlled by the pressure mechanism and operable independently of the motor for operating said controlling means.

58. In a pressure system, means operable in either of two directions for regulating. the pressure in the system, a motor for actuating the regulating means in either of the said two directions, the motor being adapted to occupy a mean average position when the pressure in the system has a mean average value, a pressure device responsive to the pressure in the, system, controlling means controlled in accordance with variations in the pressureof the system for causing step by-step operation of the regulating means by the motor in either of the said two directions, and means controlled by the pres sure device and operable independently of' the motor for operating the controlling means when the said variations attain a predetermined value.

59. In a pressure system, a reversible motor for regulating the pressure in the system and adapted to occupy a (mean average position when the pressure in the system has a mean'average value, a pressure device responsive to the pressure in the system, controlling means controlled in accordance with variations in the pressure of the system for causing step-by-step operation of the motor in either of its two opposite directions or operation, and means controlled by the pres;

0 the motor for, operating the controlling" sure device and operable independent y means when the said variations fattaina pre determined value.

60. In a pressure system,

and adapted to occupy amean average position when the pressure in the systemhas a 'mean average value and to occupy a a reversible motor for regulating the pressure in the system memo? plurality of other positions each correspon mg to a predetermined value of the pressure, an

element for controlling the starting of the motor in either of its two opposite directions of. operation, and means controlled in. ac-

cordancewith variations in the pressure of the system for actuating the element to effect the starting of the motor in either of its two opposite directions ofoperation, for no preventing the motor from starting until the said variations attain a predetermined value, and for stopping the motor when the motor has been actuated to a position cor.- responding to the value of the pressure at which the motor started.

61. In a pressuresystem, a motor for con trolling the pressure in the system, pressure controlled means-for causing a stepby-step operation of the motor, and time-lag means for ensuring the completion of the stepsoll operation: 1

62; lln a pressure system, a reversible mo= tor for controlling the pressure in the sys tem and adapted to occupy a mean average position where the pressure in the system has a mean average value, a governing ele ment for the motor,'means controlled in ac-= cordance with variations in the pressure of the system for operating said element to step-by-step operation lot" the controlling means by the motor in either of the said two directions by steps or sill) stsun'ut ially. equal lh under normal conditions and liy Oll antoma'tica'lly' vary ,lenh' tinder ah= normal conditions a 4 In testimony whereoii ll'have aiilsed my signature J A as Lewis Al "cause a step-by-step operation of. said mo- 

